This invention relates a computer keyboard platform support mechanism and, more particularly, to the construction of the linkage arm assembly that connects the keyboard platform to a support surface. Specifically the invention relates to the combination of a braking mechanism with a linkage arm assembly that allows for adjustment of tilting of the keyboard support platform relative to the linkage arm assembly and the linkage arm assembly relative to the support surface or structure.
Various apparatus and mechanisms have been developed for supporting keyboards associated with computer terminals. One such apparatus is disclosed in Smeenge U.S. Pat. No. 4,616,798 entitled xe2x80x9cAdjustable Support For CRT Keyboard.xe2x80x9d Smeenge teaches, inter alia, a keyboard support mechanism comprised of first and second sets of arms which link first and second brackets associated respectively with a keyboard platform and a sliding plate attached beneath a desk surface service. The Smeenge patent is incorporated here by reference. Subsequent patents relating to the same subject matter include: U.S. Pat. No. 5,037,054 entitled xe2x80x9cAdjustable Support Mechanism For A Keyboard Platform,xe2x80x9d issued Aug. 6, 1991 also incorporated herewith by reference.
The mechanisms disclosed in these prior patents are quite useful for supporting a keyboard on a platform adjacent to a work surface and for permitting upward and downward adjustment of that keyboard platform as well as lateral or side to side adjustment and tilt of the keyboard platform. When adjusting the elevation and attitude or tilt of such keyboard platforms, it is desirable to have a braking mechanism which maintains the keyboard platform in a fixed position by locking the arms, but which may be easily released to permit desired readjustment of the position of the platform. It is further desirable to have all of the adjustments independent, one from the other. It is also desirable to have a keyboard platform support mechanism which is compact, easily stored, of simple construction, yet rugged enough to support a significant weight. It is also desirable to have a construction which will fold away quite easily and can be easily moved from one position to another. These, among other objectives, provided an incentive for development of the present construction.
In a principal aspect, the present invention comprises a keyboard platform support mechanism which includes a keyboard support platform pivotally attached to linkage arms which, in turn, are pivotally attached to a bracket connected to a support surface. Thus, the first and second linkage arms are typically pivotally connected at their outer ends to a keyboard support platform and at their inner end to the support surface bracket. The linkage arms permit pivotal motion of the keyboard platform about a horizontal axis defining the connection between the linkage arms and the keyboard support platform as well pivotal motion about a second horizontal axis defining the connection between the support surface bracket and the linkage arms.
As an important feature of the invention, a braking mechanism is provided for [each of] the horizontal pivot connections defined at the opposite ends of the linkage arms. Thus in one embodiment, a slide rod member is pivotally attached to the keyboard support platform. That slide rod member is telescopically fitted through a housing which is pivotally attached to a linkage arm. A gripping element is integrated into the housing to engage or grip the slide rod member and retain the slide member in a fixed position within the housing, thereby precluding further pivotal movement of the keyboard support platform relative to the linkage arm. The gripping element is, however, releasable from the rod member and may thus disengage from the slide rod member, thereby permitting the slide member to assume a distinct or different telescopic position associated with pivoting or tilting of the keyboard support platform about a horizontal axis. The gripping element in a preferred embodiment, automatically returns to a gripping position upon release of a manual force that effects disengagement of the gripping element from the slide rod member. In a preferred embodiment, a brake mechanism of the type described is incorporated to control each pivotal horizontal axis connection of the linkage arms, or, in other words, the described braking mechanism is provided at each of the opposite ends of the linkage arm. Thus, a braking mechanism is included in association with the horizontal axis pivotal connection of the keyboard support platform to the linkage arms and is also provided with respect to the horizontal pivotal axis connection associated with the opposite ends of the linkage arms which effect attachment to a support surface, such as a desk, or the like.
The gripping element may be a spiral spring brake member. However, alternative gripping elements may be adopted such as a manually releasable clamp.
Further, combinations of support arms may be utilized to support a table or platform wherein one or more of the support arms will include a brake mechanism of the type disclosed. The brake mechanisms of separate arms may also be mechanically interconnected to operate in unison.
Thus, it is an object of the invention to provide an improved keyboard support mechanism which is easily adjustable and which includes a releasable brake mechanism.
Yet a further object of the invention is to provide an improved brake engagement and brake release mechanism associated with a keyboard support platform.
Yet another object of the invention is to provide a rugged, yet adjustable keyboard support platform mechanism wherein the keyboard platform is independently adjustable relative to the adjustment associated with a linkage arm supporting the platform on or by a support surface.
These and other objects, advantages and features of the invention will be set forth in a detailed description which follows: